Method of steam processing tubular knit fabric or the like

ABSTRACT

The disclosure relates to an apparatus for steam processing tubular knitted fabric, as in a spreading or calendering operation. The steamer apparatus of the invention is characterized by its ability effectively to impart steam to the fabric at much higher rates than has been possible heretofore, consistent with satisfactory quality. Since the steaming of the fabric heretofore has constituted a limiting or bottleneck stage of calendering or similar processing operations, the ability of the new steaming device to increase the effective rate of steam application can be translated directly into higher production rates in the fabric processing operation as a whole. The new steaming apparatus includes a pair of dripless steam boxes of heretofore known construction arranged above and below the plane of the fabric in a manner well known per se. According to the invention, however, these steam boxes are closely embraced and enclosed by a steam chamber housing, which momentarily confines the billowing steam in the immediate vicinity of the fabric surface. To advantage, the excess steam is removed by way of a down-draft exhaust system.

[451 Feb. 25, 1975 Unite States atent [191 Frezza METHOD OF STEAM PROCESSING [57] ABSTRACT The disclosure relates to an apparatus for steam pro- TUBULAR KNIT FABRIC OR THE LIKE cessing tubular knitted fabric, as in a spreading or calendering operation. The steamer apparatus of the invention is characterized by its ability effectively to im- [22] Filed:

[21] Appl. No.1355

part steam to the fabric at much higher rates than has been possible heretofore, consistent with satisfactory quality. Since the steaming of the fabric heretofore has constituted a limiting or bottleneck stage of calendering or similar processing operations, the ability of the new steaming device to increase the effective rate Related U.S. Application Data [62] Division of Ser. No. 348,068, April 5, 1973.

, 34/57, 34/ 158, of steam application can be translated directly into 34/160, 68/5 E higher production rates in the fabric processing operation as a whole.

The new steaming apparatus includes a pair of dripless steam boxes of heretofore known construction arranged above and below the pla ae .m C

f Gi m 010 m mA 'manner well known per se.

invention, however, these steam boxes are closely [56] References Cited UNITED STATES PATENTS embraced and enclosed by a steam chamber housing,

26/18 5 34/160 X which momentarily confines the billowing steam in the -m- /155 immediate vicinity of the fabric surface. To advantage, the excess steam'is removed by way of a down-draft exhaust system.

Cohn et al.

C 229 556 999 ill 372 .l 449 4'4 03 301 924 8000 5 b4 27-3 Primary ExaminerRobert W. Jenkins Assistant Examiner-Philip R. Coe

4 Claims, 2 Drawing Figures Attorney, Agent, or FirmMandeville & Schweiter PATENTEI] FEB 2 51975 SHEEI 1 0F 2 FIG. 1

' PATENTEB FEB 2 51975 sum 2 a: 2

N QE

r 1 METHOD OF STEAM PROCESSING TUBULAR KNIT FABRIC OR THE LIKE RELATED APPLICATIONS This application is a division of copending application Ser. No. 348,068, filed Apr. 5, 1973, entitled Fabric Calendering Systems With High Production Capacity. Reference can be made to the copending application for a more detailed description of a fabric finishing line which incorporates to advantage the apparatus of the present invention.

BACKGROUND AND SUMMARY OF THE INVENTION In processing of tubular knitted fabric, such as in the spreading to width or finish calendering treatment of the fabric, it is conventional practice to direct the tubular fabric over an internal spreading device. This device, often referred to as a spreader or propeller, distends the fabric laterally to a predetermined uniform width, typically advancing the fabric by means of longitudinally moving belts engaging the inner edge walls of the fabric. While the fabric is held in its laterally distended condition, and while it is being advanced through the finishing equipment, it is subjected to a steaming operation, to relax the fibers and enable the fabric to readjust to its laterally distended, geometrically uniform condition. To a large extent, the fabric then tends to retain this geometrical condition as it is delivered at the discharge end of the spreading device. When the finishing operation incl'udes calendering, the thus spread and steamed fabric is passed directly between a pair of calender rolls, and subsequently gathered as by folding or rolling.

Heretofore, in a fabric processing operation as described above, the overall rate of production has been limited by the ability effectively to impart steam into the fabric, to achieve the necessary fiber lubrication, relaxation and overall fabric stabilization. In this connection. merely increasing the rate of application of steam to the fabric, as by increasing steam pressure or the like, has not proven to be an effective way of increasing the overall fabric production. Thus, with conventional procedures, when an effort is made simply to increase the rate of steam application, the operator is faced with serious problems of water condensation on the fabric and on the machinery. When this occurs, the fabric becomes stained by water spots, resulting in a serious loss of quality, which may more than offset any increase in production rate. This problem has existed notwithstanding the utilization of so-called dripl ess steam discharge boxes, because the volumes of steam are such as to give rise to unwanted condensation problems after the steam has been issued from the steam boxes.

In accordance with the invention, a pair of steam boxes of known design are mounted in opposed relation on opposite sides of the plane of the fabric being conveyed by the spreader. The steam boxes have discharge slots facing the fabric, such that high velocity jets of steam are directed in opposed relation toward the plane of the passing fabric, in a generally wellknown manner. Significantly, higher production capabilities are imparted to this otherwise conventional configuration by closely embracing and confining it in a substantially enclosed steam chamber through which the fabric passes while engaged by the fabric spreader.

The specific proportions of the enclosing steam chamber are not known to be critical. However, it is consistent with the invention that there be a relative minimum of chamber volume above and below the steamers, with most of the open chamber volume being located immediately upstream and immediately downstream of the steam boxes. Further, the dimension of the steam chamber in the direction of fabric movement is significantly less than the length of the fabric spreader, permitting the spreader to extend entirely through the otherwise enclosed steam chamber.

To accommodate the passing through of the fabric spreader and the travel thereover of the fabric being processed, the steamer apparatus of the invention includes flexible sealing elements at the entry and exit openings of the steam chamber. These sealing elements are arranged to conform about the spreading device and fabric without applying any significant amount of pressure thereto, to assist in the confinement of the steam in the enclosed chamber while at the same time avoiding any pressure marking of fabric. To advantage, the flexible sealing elements may be in the form of soft brushes, for example. 2

For most effective results, the steam chamber should be provided with its own exhaust system arranged to effect removal of the excess steam at a rate somewhat corresponding to the rate of steam discharge into the chamber, while providing for a neutral or slightly positive pressure within the chamber. To greatest effect, the exhaust arrangement provides for the downward flow of the exhausting steam from regions adjacent the entry and discharge openings of the chamber. This desired configuration is achieved by providing an exhaust outlet in the bottom of the chamber in conjunction with a transversely extending baffle arrangement which forms, in effect, a false bottom of the chamber.

For a better understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description and the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a steamer apparatus constructed in accordance with the teachings of the invention, as taken for example generally on line ll of FIG. 2.

FIG. 2 is a longitudinal cross-section of the steame apparatus of FIG. 1, as taken generally on line 22 of FIG. 1.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Referring now to the drawings, the reference numeral l0 designates in a general way a typical propeller spreader apparatus for tubular knitted fabrics. By way of example only, the spreader apparatus 10 may be of the type illustrated and described in the S. Cohn, et al., US. Pats. No. 2,589,344 and 2,589,345. Typically, such spreaders involve a pair of transversely spaced, longitudinally extending frame members 11 having a plurality of guide sheaves 12 supporting propeller belts 13. A tubular knitted fabric 14 is applied over the spreader frame I0, and the frame typically is'so arranged or adjusted that the tubular knitted fabric is laterally distended to a flat, two-layered form, at a predetermined, uniform width. By means of external edge 3 drive rolls (not shown) the propeller belts 13 are driven to convey the fabric by its edges substantially over the entire length of the spreader apparatus.

In accordance with the beforementioned S. Cohn U.S. Pat. Nos. 2,589,344 and 345, the spreader apparatus typically may consist of two stages, an entry stage in which the fabric is advanced at a first predetermined speed, and a processing stage in which the fabric is conveyed at a somewhat slower speed. The speed differential thus provided accommodates a lengthwise relaxation or overfeed of the fabric as it traverses the processing stage.

During the traverse of the fabric over the processing stage, it is subjected to steaming, to lubricate the fibers and the yarns and enable the necessary'readjustment and repositioning thereof to occur, such that the fabric is substantially stabilized in its laterally distended condition, and has a substantially uniform width.

FIG. I illustrates a portion of the processing stage of the spreader, which extends entirely through a steam processing chamber 15. Within the processing chamber 15 there are mounted a pair of transversely disposed steam boxes 16, 17, which extend across the full width of the machine, immediately above and below the plane of the spreader frame 10. In general, the construction of the steam boxes 16, I7 follows the teachings of the S. Cohn, et al., U.S. Pat. No. 2,602,314, granted July 8, 1952. In this respect, each steam box includes a steam pipe 18 extending transversely throughout the entire length of the steam box, typically being connected with an appropriate steam supply line 19 at both ends, or, in the alternative, at one end with a cap (not shown) at the other end. Within the confines of the steam box housing proper, the pipe 18 may be provided throughout with a plurality of steam distributing apertures 20. As is evident in FIG. 1, the upper and lower steam boxes 16, 17 are of generally similar construction, with certain exceptions to be noted, so that both boxes can be described with particular reference to the upper box 16, as a matter of convenience. To advantage, the staem box includes an outer housing 21 of generally rectangular cross-sectional configuration and having opposed side walls 22, 23 and an upper or back wall 24. At the lower or front extremities of the side walls. there are inturned lips 25, 26 joined to upwardly directed flanges 27, 28. At each end. the steam box has an end wall 29.

Received within the above described configuration of walls is an inner chamber-forming member 30 formed of sheet metal and having a front or bottom wall 13, vertically extending side walls 32, 33, and inturned flanges 34, 35 extending toward but terminating in spaced relation to the steam pipe 18.

As will be evident in FIG. 1, the upwardly extending flanges 27 and 28, in conjunction with the vertical side walls 32, 33 of the chamber-forming member 30, define vertically elongated steam passages 36, 37, which extend transversely across substantially the entire width of the steam box.

Steam issuing from the apertures in the steam pipe is directed toward the blind or closed wall 31 of the inner chamber, and then is forced to flow upward, around the pipe and out through the transversely elongated openings between the pipe and the inturned flanges 34, 35. The steam then flows outward and downward through the spaces 38, 39 between the respective pairs of side walls 22, 32 and 33, 23, toward box itself, so that the issuing steam jets do not carry with them any large drops of water to saturate and stain the fabric. In this respect, the blind wall 31 of the inner chamber forms a first condensate collector. In addition, further condensate is collected in the transversely extending trough formed between the flanges 27, 28

- and side walls 22, 23. Any condensate collected in these areas is permitted to drain through an opening 40 in the end wall, passing out through an elbow fitting 41 and drain pipe 42.

In the case of the lower steam box 17, because of the reverse orientation thereof and the arrangement of upwardly opening steam jets 36a and 37a, condensate traps are formed at 43, 44 by the inturned flange lips 34a, 35a and by the blind back or bottom wall 24a of the steam box. Collected condensate is discharged through an opening 45 and flows out through an elbow fitting 46 and drain pipe 47. Thus, in either the downward or upward orientation of the steam box, condensate developed internally of the box is substantially prevented from issuing through the steam jets.

The upper steam box 16 advantageously is insulated along its side walls 22, 23 and its upper wall 24. For this purpose, slabs 48 of insulating material are secured by spaced metal straps 49. This minimizes formation of condensate on the outside of the upper steam box, which could drip down on the passing fabric. This is not a problem, of course, with the lower steam box, for which the insulation may be omitted.

In accordance with the present invention, the two steam boxes 16, 17 are closely enclosed and confined by the walls of the processing chamber 15. In the illustrated arrangement, the processing chamber 15 has a more or less octagonal configuration, although this is not known to be critical. To this end, the chamber 15 is provided with an upper wall 50 which joins with front and back upper sidewalls 51, 52. The walls 50-52 extend the full width of the machine and are joined by end walls 53.

To advantage, the upper walls 50-52 are of insulated construction, including panels of insulating material 54 between plates of sheet metal. The upper wall 50 is rigidly connected to the endwalls 53, while the front and back upper side walls 51, 52 are advantageously connected to the upper wall 50 by means of hinges 55, 56. This enables the walls 51, 52 to be pivoted upwardly, to the positions shown in broken lines in FIG. 1, to provide easy physical access to and observation of the interior of the chamber 15 when desired. Outwardly bent flanges 57 formed on the end walls 53 serve to support the hinged walls 51, 52 in their operative or closed positions.

As is evident in FIG. 1, the upper sidewalls 51, 52 extend downward and outward from their upper edges to a level corresponding generally with the bottom of the steam box 16. These walls extend at an angle of about 45 to the horizontal, defining in part confined processing areas immediately upstream and downstream of the steam box 16 and immediately above the plane of the fabric spreader l0.

The processing chamber 15 also has a bottom wall 60, spaced well below the lower steam box 17, and front and back bottom sidewalls 61, 62 extending upwardly and outwardly therefrom. In addition, there are provided sidewalls 63, 64 extending upward from the upper, outer extremities of the bottom sidewalls and terminating a short distance below the plane of the fabric spreader 10. The several walls 60-64 extend across the full width of the chamber 15 and are connected by the end walls 53. Together with the upper walls 50-52, the walls 60-64 form a substantially complete enclosure provided with entry and exit openings 65, 66 in the form of relatively narrow elongated transverse slots at the upstream and downstream extremities to receive the spreader frame and the fabric 14 passing thereover.

Directly underneath the lower steam box 17 is a baffle plate structure comprising a lower baffle wall 67 from which walls 68, 69 extend upwardly and outwardly. The baffle 67-69 forms confined processing areas of generally triangular cross-section immediately upstream and downstream of the lower steam box 17 and generally opposing the similar processing areas formed in the upper portion of the chamber. The baffle structure typically is supported from the bottom sidewalls 61, 62 of the chamber by means of spacer posts 70, 71, providing an open channel 72 between the baffle and the bottom structure 60-62.

In the illustrated arrangement of apparatus, the lower channel or passageway 72 is open at its upstream and downstream extremities 73, 74, which are adjacent the transversely elongated entry and exit openings 65, 66 to the chamber. In addition, there is provided a downdraft exhaust outlet 75 in the lower portion of the chamber, which is connected to a suitable exhaust blower (not shown). To greatest advantage, the exhaust blower is so constructed and/or controlled, with respect to the rate of flow of steam being ejected into the interior of the processing chamber 15, that a slight positive pressure is maintained within the chamber. In this respect, it is acceptable for some amount of the steam to escape from the chamber through the inlet and outlet openings 65, 66.

Suitable arrangements (not shown) are typically provided for removal of steam condensate from the lower portion of the processing chamber. To this end, the baffle plate structure 67-69 may accommodate the drainage therefrom into the lower portion of the chamber, as by providing suitable clearance spaces at the ends, and a suitable drainage outlet may be provided in the bottom wall 60 for the continuous or periodic removal of collected condensate.

In accordance with a specific aspect of the invention, the transversely elongated entry and exit openings 65, 66 are provided with flexible sealing means adapted to lightly contact and conform to the surface of the passing fabric to inhibit the escape of steam from the processing chamber. To advantage, the flexible sealing means may comprise soft brushes 75 mounted on brackets 76, 77 secured to the walls of the chamber immediately above and below the entry and exit openings 65. 66. The soft brushes 75 lightly contact the surface of the moving fabric 14 in the manner shown in FIG. 1. While by no means forming a tight seal, the sealing brushes 75 do partly impede the outflow of the steam from the processing chamber 15, which is ideally maintained at only a slight positive pressure with respect to the ambient.

In some instances, where highly effective exhaust hood means are provided in the immediate vicinity of the steam chamber 15, it may be at least marginally acceptable to permit all of the excess steam to escape through the entry and exit openings 65, 66, to be immediately collected and withdrawn by a closely adjacent forced draft exhaust hood.

As is reflected in FIG. 1, the cross-sectional dimensions of the processing chamber 15 are such, in relation to the dimensions of the steam boxes 16, 17, that the excess steam, after issuing from the steam discharge openings 36, 37 and 36a, 37a and passing through the fabric, is at least temporarily confined within the processing chamber, in close proximity to the steam boxes and in contact with the surfaces of the fabric. Because of the thermal insulation provided on the upper walls 50-52 of the processing chamber, steam condensation on these walls is minimized to an acceptably low level,

' so that it does not adversely affect the production.

The additional temporary confinement of the excess steam in contact with the fabric immediately following its issuance from the steam boxes proper, greatly enhances the ability of the process to achieve the desired levels of steam penetration of the fabric within a short period of time. As a result, it is possible to significantly increase the speed of passage of the fabric 14 through the steam processing chamber, still achieving adequate levels of steam penetration but without experiencing spotting or staining of the fabric from condensation. In practice, this has enabled the production speed of the steaming operation to be doubled in some cases. And since the steaming operation has represented the bottleneck of the fabric finishing procedure, it has been thus made possible in those cases to double the production rate of the finishing procedure as a whole.

For most applications, the invention achieves greatest effectiveness utilizing a forced draft exhaust means in conjunction with the steam chamber, so that the excess steam is ducted directly away from the chamber. This enables a maximum rate of steam application to be utilized, without exposing the related equipment to excessive amounts of free steam, which could result in undesirable condensation. Utilizing a forced draft exhaust, while maintaining a slight positive pressure within the steam chamber, keeps to a practical minimum the volume of escaping steam.

To greatest advantage, the forced draft steam exhaust is provided in the lower portion of the steam chamber, with its intake means adjacent the entrance and exit openings to the chamber. This arrangement assures that the out-flowing steam will have maximum exposure to the fabric in relation to the relatively small size of the confined processing region.

It should be understood, of course, that the specific form of the invention herein illustrated and described is intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.

I claim:

I. The method of steam processing tubular knitted fabric or the like, which comprises a. spreading the fabric to generally flat form and conveying it along a predetermined, generally horizontal processing plane,

b. directing opposed jets of processing steam at high velocity toward, and at a large angle to the principal flat surfaces of the fabric from opposite sides, across its width,

c. said processing steam being directed into contact with said fabric in the form of high velocity jets which are effectively continuous across the width of the fabric,

d. at least temporarily confining the steam thus ejected to limited upper and lower regions immediately adjacent to the fabric on opposite sides, and thereafter e. withdrawing downwardly steam from the said limited regions at a rate sufficient to prevent substantial condensation of steam within said upper region in areas directly above the fabric,

f. steam from said upper region being withdrawn downwardly through said fabric.

i 2. The method of claim 1, further characterized by a. said steam being initially applied to the fabric in two or more directly opposed pairs of high velocity steam jets extending substantially continuously across the full width of the fabric,

b. said steam, after initial application, flowing into and being temporarily confined in said limited regions.

3. The method of claim 1, further characterized by a. said spreading and conveying step being carried by overfeeding said fabric to said processing plane. 4. The method of claim 1, further characterized by a. the steps of directing said steam jets and of withdrawing said steam being so related as to maintain said upper and lower limited regions under at least a slight positive pressure, relative to ambient, during normal operation. 

1. THE METHOD OF STEAM PROCESSING TUBULAR KNITTED FABRIC OR THE LIKE, WHICH COMPRISES A. SPREADING THE FABRIC TO GENERALLY FLAT FORM AND CONVEYING IT ALONG A PREDETERMINED, GENERALLY HORIZONTAL PROCESSING PLANE, B. DIRECTING OPPOSED JETS OF PROCESSING STEAM AT HIGH VELOCITY TOWARD, AND AT LARGE ANGLE TO THE PRINCIPAL FLAT SURFACES OF THE FABRIC FROM OPPOSITE SIDES, ACROSS ITS WIDTH, C. SAID PROCESSING STEAM BEING DIRECTED INTO CONTACT WITH SAID FABRIC IN THE FORM OF HIGH VELOCITY JETS WHICH ARE EFFECTIVELY CONTINUOUS ACROSS THE WIDTH OF THE FABRIC, D. AT LEAST TEMPORARILY CONFINING THE STEAM THUS EJECTED TO LIMITED UPPER AND LOWER REGIONS IMMEDIATELY ADJACENT TO THE FABRIC ON OPPOSITE SIDES, AND THEREAFTER E. WITHDRAWING DOWNWARDLY STEAM FROM THE SAID LIMITED REGIONS AT A RATE SUFFICIENT TO PREVENT SUBSTANTIAL CONDENSATION OF STEAM WITHIN SAID UPPER REGION IN AREAS DIRECTLY ABOVE THE FABRIC, F. STEAM FROM SAID UPPER REGION BEING WITHDRAWN DOWNWARDLY THROUGH SAID FABRIC.
 2. The method of claim 1, further characterized by a. said steam being initially applied to the fabric in two or more directly opposed pairs of high velocity steam jets extending substantially continuously across the full width of the fabric, b. said steam, after initial application, flowing into and being temporarily confined in said limited regions.
 3. The method of claim 1, further characterized by a. said spreading and conveying step being carried by overfeeding said fabric to said processing plane.
 4. The method of claim 1, further characterized by a. the steps of directing said steam jets and of withdrawing said steam being so related as to maintain said upper and lower limited regions under at least a slight positive pressure, relative to ambient, during normal operation. 